Should any voter to whom any official ballot has been handed spoil or render the same unfit for use, he may return it and obtain another from the district board, but no more than two official ballots shall be furnished to any voter, except at the discretion of the board.

The board shall preserve all the ballots, with their coupons attached, returned by a voter as spoiled or unfit for use, and after the proper correction has been made in the poll book and signature copy register or register of voters such ballot or ballots shall be placed upon the same string with the coupons.